Facility for recycling the components of defective or used fluorescent tubes

ABSTRACT

A system ( 100 ) for recycling the components of defective or spent fluorescent tubes ( 3 ) comprises a conveying device ( 15 ), on which the fluorescent tubes ( 3 ), which are arranged parallel to each other, adjacent to each other and perpendicular to the conveying device, can be conveyed past processing stations ( 22, 28, 36, 38, 40 ) in a substantially horizontal manner. There is a feed station ( 5 ) for feeding the delivered fluorescent tubes ( 3 ) to the conveying device ( 15 ). The processing stations comprise a perforating station ( 22 ), where a hole in the glass tube ( 30 ) can be produced at least on one end of the fluorescent tubes ( 3 ) for the purpose of relieving the negative pressure prevailing in the glass tube; comprise a severing station ( 36 ) for severing the sealing and connecting caps ( 32 ) from the glass tube ( 30 ) of the respective fluorescent tube ( 3 ); comprise a blow-out station ( 38 ), where the phosphor ( 31 ) is blown out of the respective glass tube ( 30 ) by means of a blast of air along the length of said tube, and comprise a breaking station ( 40 ), where the glass tube ( 30 ) can be comminuted into free-flowing fragments. The conveying device ( 10 ) can be driven continuously; and the perforating station ( 22 ) has on at least one end and the severing station has on both ends of the respective fluorescent tubes ( 3 ) burner strips ( 23 ) with adjacent nozzle orifices ( 26 ), which are arranged close together in a row arranged in a straight line in the conveying direction and which melt the ends of the glass tube ( 30 ) into the shape of a slit. (FIG.  1 ).

BACKGROUND OF THE INVENTION

The invention relates to a system for recycling for the purpose ofre-utilizing the components of defective or spent fluorescent tubes.

For lighting purposes in offices, in public areas, workshop halls etc.,one usually uses fluorescent lamps that are made of a straight glasstube, whose inside circumference is coated with a fine luminescentpowder and whose interior is filled with a low pressure gas. This typeof tubular fluorescent lamp is called a fluorescent tube. The ends ofthe glass tube are sealed and provided with a metal connecting base,which bears contact pins. These universal fluorescent tubes have only alimited life and, therefore, rapidly fall into a defective or spentstate. Their components, namely the glass tube, the connecting base andthe content material, namely phosphors and mercury, are largelyrecyclable. For this reason the fluorescent tubes are collected forrecycling the components on pallets with suitable superstructures, onwhich the tubes are deposited in ordered layers.

To recycle the components of these fluorescent tubes there exists asystem that comprises a raised longitudinal stage, on whose one end thepallets with the fluorescent tubes can be deposited. Attached to thepallet region in the longitudinal direction is an essentially closedhousing, which has a lift beam conveyor, which conveys the fluorescenttubes step-by-step forward, moving them past several processing stationsin the housing.

In the feed station the fluorescent tubes are fed manually to a shortchain conveyor, where at one end of the conveyor the fluorescent tubesare transferred to the lift beam conveyor.

The processing stations in the housing comprise, first of all, aperforating station, in which stationary oxyhydrogen burners direct avery concentrated thin flame on the glass tube in the vicinity of therespective cap and burn a small hole in the glass tube. The air can flowthrough this small hole into the fluorescent tube in order to produce apressure equilibrium.

Then the fluorescent tubes are carried past a severing station, wherethe fluorescent tubes are turned and the glass tube in the vicinity ofthe respective cap is severed, i.e. cracked off, using another burner.

Next is a blow-out station, in which a strong blast of air is sent fromone side through the glass tube, which has been freed of its caps. Theair blows out the bulk of the fine luminescent powder adhering to theinside circumference of the glass tube through the other end of theglass tube.

Finally the cleaned glass tube is comminuted into small free-flowingfragments or splinters.

The caps, the glass and optionally the content materials are collectedand fed to recycling. When the recycling of the content material cannotbe justified from an economic view point, dumping, e.g. undergroundlandfill, may also be considered.

The existing system has functioned for years satisfactorily, but itsefficiency is limited. Namely the single fluorescent tube must remain inthe perforating station and in the severing station until the burner hascreated the hole. This intermittent method is time-consuming.

SUMMARY OF THE INVENTION

The invention is based on the problem of providing a system of this typethat is more efficient.

The problem is solved by the present invention.

In contrast to the lift beam conveyor, a continuously working conveyorin combination with the burner strips, which extend a certain distancein the conveying direction, instead of the stationary point flame in theperforating station and in the severing station greatly multiples thesystem's productivity. Tests have demonstrated that a single system canprocess 11,000 fluorescent tubes per hour.

In one preferred embodiment of the invention, the conveying devicecomprises two chain conveyors, which revolve continuously side-by-sidein vertical planes and are spaced apart so as to match the length of thecommercial fluorescent tubes and whose upper runs carry the fluorescenttubes.

To decouple the work in the processing stations from the fluorescenttube feed, it is advisable to connect to the conveying device a transferconveyor, onto which the fluorescent tubes can be fed in an orderedmanner and by means of which the fluorescent tubes can be deliveredindividually to the conveying device.

The transfer device can comprise a conveyor, followed by a separatingunit.

In order to eliminate the manual feed of the fluorescent tubes in thefeed station and the accompanying risk to this person performing thetask should one of the fluorescent tubes break, the feed station cancomprise a grasping device, by means of which at least one portion of alayer of fluorescent tubes can be grasped at one time and put on thetransfer conveyor.

The grasping device can comprise a suction member, which can raisethrough the suction effect the relatively light fluorescent tubes out ofthe layer and release them again by way of the transfer conveyingdevice.

The suction member can comprise in particular a suction frame, which isadapted to the layout of the layer or a portion of the layer offluorescent tubes. The suction frame can be suspended from a liftingdevice, which is provided with a boom that can be swung up or down androtated around a vertical axis.

The severing station can comprise a burner strip which extends in theconveying direction at both ends of the fluorescent tubes.

The burner strip, which is used both in the perforating station and inthe severing station, can exhibit an effective length ranging from 100to 300 mm and a longitudinal housing with thirty to eighty nozzleorifices, whose diameters range from 0.2 to 0.4 mm and which areprovided, when in operation, on a side facing the fluorescent tubes.

A small number of all of the fluorescent tubes under discussion areprovided for use in environments subjected to the risk of explosion andbear metal strips, normally copper strips, which run parallel to theaxis over the entire length of the outside of the glass tube, in orderto avoid sparks. The copper may not get into the recycled comminutedglass, because it causes a discoloration of the glass during theremelting process.

For this reason such special fluorescent tubes must be excluded from therecycling process.

This occurs with the aid of the detector, which interacts with asuitable separating unit, by means of which the fluorescent tubes,provided with copper strips, can be excluded from the recycling so thatthe copper cannot get into the recycled glass. The detector can work,for example, optically by detecting the reflection differences when thecopper strip on the rotating fluorescent tube passes.

Important embodiments of the invention include features permitting thedetection of fluorescent tubes, filled with different phosphors, and asorting by the type of phosphor that is blown out. A device to detectdifferent fluorescent tubes by their different types of luminescentpowder is known, for example, from the WO 98/04904.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is depicted as a schematic drawing.

FIG. 1 depicts the severed right end of a fluorescent tube.

FIG. 2 is a side view of the system, according to the invention.

FIG. 3 is a view of the system, according to FIG. 2, from the left.

FIG. 4 is a perspective view of a burner strip.

FIG. 5 is a view of the suction frame.

FIG. 6 is a view, according to FIG. 5, from the left.

FIG. 7 is a top view, according to FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the severed right end of a fluorescent tube 3. Thefluorescent tube 3 comprises a glass tube 30, which is 50 to 180 cm longand has a diameter ranging from 2 to 4 cm. The glass tube interior has acoat of fine luminescent powder, which adheres to the inside wall of theglass tube 30 and is shown in FIG. 1 with dots 31. Both ends of thefluorescent tube are sealed by a melted-on stem, which is made of leadglass and bears the lead wires and the filament. On the outside a metalconnecting base 32, which exhibits the contact pins 33 for theelectrical connection, is cemented to both ends of the fluorescent tube.The glass tube 30 is evacuated, with the result that applying current tothe contact pins 33 will produce a gas discharge, which causes themercury-containing phosphor 31 to glow. 34 marks the severing point, atwhich the end of the fluorescent tube with the connecting base 32 issevered in the recycling system to be described below. The outercircumference of explosion-protected fluorescent tubes 3 exhibits acopper strip 8, which can be detected by a device (to be describedbelow) for the purpose of sorting out such fluorescent tubes 3.

The recycling system, all of which is marked with the reference numeral100 in FIG. 2, is arranged on a stage 1, which is provided at a heightof about 2 to 3 m above the ground 2 and has the purpose of providingspace under the actual system 100 for classifying and setting upcontainers for the recycled components of the fluorescent tubes 3. Onemust use ladders 4, 4′ to climb to the stage 1.

The left side of the stage 1, depicted in FIG. 2, has a feed station,all of which is marked with the reference numeral 5. The defective orspent fluorescent tubes 3 are delivered on pallets with their ownsuperstructure, which are indicated by the triangle 6 in FIG. 2 and canbe deposited on the stage 1 by a lifter. The fluorescent tubes 3 arestacked side-by-side on the pallets 6 in ordered horizontal layers 7 soas to form a dense package. Next to the region, on which the pallets 6are deposited, there is a lifting device 10, which comprises a column11, on which a boom 12 can be rotated around a vertical axis 9. Inaddition, the boom 12 can be swung up and down in the direction of thearrow. Suspended from the free end of the boom 12 is a suction frame,all of which is marked 20 and which is connected by means of vacuumlines 48 to a vacuum pump or other device to generate a vacuum.

The suction frame 20 is lowered from the top onto a layer 7 offluorescent tubes 3 and grasps them when the vacuum is switched on. Inthe embodiment illustrated in FIG. 1, the suction frame 20 grasps onlyone portion of a layer 7, namely seven fluorescent tubes, which do nothave to cover the entire stretch of the suction frame 20. Hence thesuction frame 20 can also lift a few fluorescent tubes lyingside-by-side.

The suction frame 20 is moved from the position, shown in FIG. 2, by wayof a transfer conveyor 13, onto which the fluorescent tubes 3 aredeposited and can be conveyed in the direction of the arrow by means ofa suitable conveyor, e.g. by means of a chain conveyor. At the end ofthe conveyor's route there is at 14 a separating unit, by means of whichthe fluorescent tubes 3 are deposited at specified intervals on aconveyor 15, which will be described in detail below. The conveyingdevice 15 is encompassed by a housing 16, which is provided with sealedwalls due to the risk of splinters should a fluorescent tube 3 break.The walls have windows, which make it possible to watch the work beingperformed in the housing 16. The housing 16 is under a slight negativepressure so that no mercury vapor can escape into the environment.

The housing 16 has two chain conveyors 17, 18, which run parallel toeach other and whose chains revolve over deflecting rollers 21 or 21′,which are arranged at the beginning and at the end of each respectivechannel 19. The upper runs 17′, 18′ of the chain conveyors 17, 18 carryfluorescent tubes 3, which are arranged perpendicular to their conveyingdirection and maintain a specified distance from each other, as evidentfrom FIG. 3. FIG. 3 does not exhibit the suction frame 20 at the boom 12for the sake of clarity. The conveying direction runs vertically to thedrawing plane of FIG. 3.

It is evident from the embodiment in FIG. 3 that the conveying device 15can be adjusted for relatively short fluorescent tubes 3. Thus the chainconveyors 17, 18 are arranged perpendicular to the conveying directionand rather close together. However, the chain conveyor 18 can be set inthe direction of the arrow 24 perpendicular to the conveying directionin order to adjust the recycling system 100 to the different lengths ofthe fluorescent tubes 3.

The fluorescent tubes 3 are carried along by the conveying device 15 toseveral processing stations, as evident from FIG. 2. The firstprocessing station is a selecting unit 60, which acts on one end of thefluorescent tubes 3 and which comprises an excitation source forexciting the phosphor coating 31 of the fluorescent tubes 3 and aspectroscopic detecting agent for detecting the light emitted by thephosphor coating 31. The fluorescent tube 3 is categorized into several,for example, three groups using the emission spectrum. The contentmaterials of the tubes, in particular the phosphors, are collectedseparately. The next station is a perforating station 22 , whose one endapprox. 200 mm from the connecting base 32 of the fluorescent tubes 3comprises a burner strip 23, which extends parallel to the conveyingdirection of the conveyor device 15 and of which one embodiment isdepicted as a schematic drawing in FIG. 4. The burner strip 23 comprisesa longitudinal housing 24 with a narrow side face 25, which tapers offinto the shape of a roof and in which a plurality of nozzle orifices 26,(in the embodiment there are 41 nozzle orifices), in the shape of fineboreholes with 0.3 mm diameter are spaced apart at short intervals 27,forming a straight row. The burner strip 23 is charged with oxyhydrogengas and produces on the whole a blade-like flame of a very hightemperature that melts the glass at one point on the ends of the glasstube, which does not rotate as it passes the burner strip 23. Since theburner strip 23 extends in the conveying direction, there is adequatetime for the glass to melt at one point and for the air to flow into theevacuated interior of the fluorescent tubes and thus to generate thepressure equilibrium, as the fluorescent tubes 3 move forward incontinuous motion.

After the perforating station 22 there is a relief station 28 with anoblong burner 29, which is arranged in the conveying direction at oneend of the fluorescent tubes 3. Said burner is in the region where theburner strip 23 of the perforating station 22 acts on the tubes; thatis, approx. 200 mm from the end of the respective fluorescent tubes 3.Said burner, which can be operated with natural gas and compressed air,maintains the temperature at the ends of the glass tube 30 in order toavoid breakage due to stress.

In the severing station 36 there are other burner strips 23′ at bothends of the fluorescent tubes 3. In this station the fluorescent tubes 3are rotated by a device (not illustrated), comprising a continuouslyrevolving belt, which engages at the periphery of the fluorescent tubes3. The tubes come to rest on a ramp (not illustrated) so that, whenpassing the burner strip 23′ of the severing station 36, the glass tube30 is heated in a narrow zone around and along the line 34 (FIG. 1) inthe immediate vicinity of the stopper and connecting cap 32. Followingthe burner strip 23′ of the severing station 32, there is a coolingsection 62, a so-called cold knife, where a cold knife-like air jet isaimed at the pre-heated narrow zone, thus blasting off the respectiveglass tube 30 along the line 34 (FIG. 1). The blasted-off ends arecaught with the connecting bases and collected for recycling.

The detector 39, provided above the region of the burner strip 23′,where the fluorescent tube 3 is rotating, detects fluorescent tubes witha copper strip 8 (FIG. 1), which are removed from the process, forexample broken, by a separating unit (not illustrated) and conveyed intothe hopper 62.

The glass tube 30, which is freed at this point of the sealing andconnecting caps 32, passes then into the blow-out station 38, where itis held by a hold-down 37 on the chain conveyors 17, 18. This process isnecessary because in the blow-out station 38 a strong blast of air blowsthe phosphor 31 (FIG. 1) from one end to the other end of the glass tube30. The air is directed through each glass tube 30 by means of a blastnozzle. The phosphor is separated from the air stream in a cyclone (notillustrated) and fed to a catch basin.

There are as many pairs of blast nozzles and cyclones as the selectingunit 60 can differentiate types. Each type is allocated a blast nozzleand a cyclone. The selecting unit has already recognized which type ofcontent material a specific fluorescent tube 3 contains. For thisspecific fluorescent tube 3 only the blast nozzle is put into actionthat is provided for the relevant type. In this manner the contentmaterial of the different fluorescent tubes is sorted.

The blown-out glass tubes 30 fall into a breaker 40, which is onlyindicated schematically and in which they can be comminuted intofree-flowing small pieces, which fall through a channel 41 into atransport container 42, which is transported to the lamp manufacturer,where the glass material is remelted.

FIGS. 5 to 7 show the suction frame 20 in detail. It is suspended bymeans of a connecting link 43 to the boom 12, whose bottom end isfastened in the middle of the cross beam 44, whose both ends bearparallel suction beams 45, which extend at right angle to the cross beam44. The suction beams 45 comprise in the embodiment four separatesuction chambers 46, which are shaped like funnels and whose upper endsexhibit fittings 47 for the connection of the vacuum lines 48 (FIGS. 2).

The suction chambers 46 attach themselves with their flexible bottomedges 50, as evident from the figures, to the layer 7 of the fluorescenttubes by means of suction. The fluorescent tubes 3 are so light thatthey can be lifted from the pallet 6 by this method as shown in FIG. 2and transferred to the delivery conveyor 13. To avoid unnecessarypressure losses, there can be a controller, which turns off the suctionchamber 46 as soon as the mouth of the same is not or is inadequatelycovered. For this reason the individual suction chambers 46 haveseparate vacuum lines 48.

What is claimed is:
 1. System for recycling for the purpose ofre-utilizing the components of defective or spent fluorescent tubes,which are made of a straight glass tube, which exhibits a gas fillingunder low pressure, a coating of a fine luminescent powder applied onthe inside circumference of the glass tube and whose two ends exhibitmetal connecting bases, comprising a conveying device, on which thefluorescent tubes, which are arranged parallel to each other, adjacentto each other and perpendicular to the conveying device, can be conveyedpast processing stations in a substantially horizontal manner,comprising a feed station, which precedes the conveying device in orderto feed the delivered fluorescent tubes to the conveying device,comprising a perforating station, where a slit in the glass tube can beproduced at least on one end of the fluorescent tubes for the purpose ofrelieving the negative pressure prevailing in the glass tube, comprisinga severing station for severing the sealing and connecting caps from theglass tube of the respective fluorescent tube, comprising a blow-outstation, where the phosphor is blown out of the respective glass tube bymeans of a blast of air along the length of said tube, and comprising abreaking station, where the glass tube can be comminuted intofree-flowing fragments, characterized in that the conveying device canbe driven continuously and that the perforating station has on at leastone end and the severing station has on both ends of the respectivefluorescent tubes burner strips with adjacent nozzle orifices, which arearranged close together in a row arranged in a straight line in theconveying direction and which melt the ends of the glass tube into theshape of a slit.
 2. System, as claimed in claim 1, characterized in thatthe conveying device has two chain conveyors, which revolve continuouslyside-by-side in vertical planes and are spaced apart so as to match thelength of the fluorescent tubes and whose upper runs carry thefluorescent tubes.
 3. System, as claimed in claim 2, characterized inthat the conveying device follows a transfer conveyor, onto which thefluorescent tubes can be transferred in an ordered manner and by meansof which the fluorescent tubes can be delivered individually to theconveying device.
 4. System, as claimed in claim 3, characterized inthat the transfer conveyor comprises a conveyor, followed by aseparating unit.
 5. System, as claimed in claim 1, characterized in thatthe feed station comprises a grasping device, by means of which at leastone portion of a layer of fluorescent tubes can be grasped at one timeand put on the transfer conveyor.
 6. System, as claimed in claim 5,characterized in that the grasping device comprise a suction member. 7.System, as claimed in claim 6, characterized in that the suction membercomprises a suction frame, which is adapted to the layout of the layeror a portion of the layer of fluorescent tubes.
 8. System, as claimed inclaim 7, characterized in that the suction frame is suspended from alifting device, which is provided with a boom that can be swung up ordown and rotated around a vertical axis.
 9. System, as claimed in claim1, characterized in that the severing station comprises a burner strip,which extends in the conveying direction in the region of both ends ofthe fluorescent tube.
 10. System, as claimed in claim 9, characterizedin that a device for rotating the fluorescent tube around its axis whilepassing the burner strip is assigned to the burner strip.
 11. System, asclaimed in claim 10, characterized in that the device comprises a rampon the inside next to each burner strip and on this ramp rest thefluorescent tubes, which are conveyed horizontally by the conveyor androtate so as to roll around their axis as they are carried along. 12.System, as claimed in claim 10, characterized in that following theburner strips there is a device for producing a knife-like cool air jetfor blasting off the ends of the fluorescent tubes.
 13. System, asclaimed in claim 1, characterized in that the burner strips exhibit aneffective length ranging from 100 to 300 mm.
 14. System, as claimed inclaim 13, characterized in that the burner strips exhibit a longitudinalhousing with thirty to eighty nozzle orifices, whose diameters rangefrom 0.2 to 0.4 mm and which are provided, when in operation, on a sidefacing the fluorescent tubes.
 15. System, as claimed in claim 1,characterized in that in the area of the burner strips there is adetector, by means of which fluorescent tubes, provided with metalstrips that run parallel to their axis on the outside circumference, canbe detected and can be excluded from further processing in the system bya separating unit, which interacts with the detector.
 16. System, asclaimed in claim 1, characterized in that in the area of the burnerstrips there is a detector, by means of which fluorescent tubes,provided with metal strips that run parallel to their axis on theoutside circumference, can be detected and can be excluded from furtherprocessing in the system by a separating unit, which interacts with thedetector.
 17. System, as claimed in claim 16, characterized in that theblow-out station comprises several blast nozzles, which follow insuccession in the conveying direction and which are assigned to a typeand which interact with a catch basin for the blown-out material of thefluorescent tube.
 18. System, as claimed in claim 17, characterized inthat there is a controller, which is attached to the selecting unit andby means of which, when a specific fluorescent tube passes by, thatblast nozzle can be activated that is assigned to the type of phosphorcontained in the fluorescent tube.